Use of tyrosine kinase inhibitors for treating cns disorders

ABSTRACT

The present invention relates to a method for treating CNS disorders, more particularly selected from the group consisting of depression, schizophrenia, anxiety, migraine, memory loss, pain and neurodegenerative diseases, comprising administering a compound capable of depleting mast cells to a human in need of such treatment. Such compounds can be chosen from tyrosine kinase inhibitors and more particularly non-toxic, selective and potent c-kit inhibitors. Preferably, said inhibitor is unable to promote death of IL-3 dependent cells cultured in presence of IL-3.

The present invention relates to a method for treating CNS disorders,more particularly selected from the group consisting of depression,schizophrenia, anxiety, migraine, memory loss, pain andneurodegenerative diseases, comprising administering a compound capableof depleting mast cells to a human in need of such treatment. Suchcompounds can be chosen from tyrosine kinase inhibitors and moreparticularly non-toxic, selective and potent c-kit inhibitors.Preferably, said inhibitor is unable to promote death of IL-3 dependentcells cultured in presence of IL-3.

Neurons propagate a signal in the form of an action potential along itsaxon to other neurons or to effector cells. Many positive or negativesignals are exchanged between neurons and are integrated to producemeaningful firing patterns. The communication between two neurons isbased on the action of numerous neurotransmitters on specific receptorslocated at the synapses. A disruption in the regulation ofneurotransmission is responsible for neurologic and psychiatricdiseases. Furthermore, the activity of neurotransmitters on theirrespective receptor is normally time limited so that receptors canrespond repeatedly to the next waves of stimuli. In this regard,different mechanisms abolish the action of neurotransmitters: they canbe pumped back into the presynaptic nerve terminals by active processes(reuptake), they can be destroyed by enzymes, or they simply diffuseinto the surrounding area.

According to The Merck Manual of Diagnosis and Therapy, Section 14,Neurologic Disorders, changes in neurotransmitter synthesis, storage,release, or degradation or changes in the number and affinity ofreceptors can affect neurotransmission and cause clinical disorders.

Among neurotransmitters, we can cite glutamate and aspartate, which arethe major excitatory neurotransmitters, whereas aminobutyric acid (GABA)is the major inhibitory neurotransmitter in the brain. But, the firsttheory about depression concerned the noradrenergic system (NS)(Shildkraut J. et al. 1965, Am J. Psychiat. 122, 509-522). At that time,it was observed that tricyclic compounds (ADT) and monoamine-oxidaseinhibitors modified the level of noradrenaline. Later on, in 1978,Sulser F. et al., Biochem Pharmacol. 27, 257-261 showed that theseantidepressants lead to a decrease in the number of post-synapticβ-adrenergic receptors. Therefore, it was thought that depression wasdue to the deregulation of the noradrenergic pre-synaptic stimuli aswell as the post-synaptic receptors (Siever LJ. et al. (1985), Am. J.Psychiat. 142, 1017-1031). In 1986, Rasmussen et al., Brain Res. 385,395-400 demonstrated the presence of serotonin (5-hydroxytriptamin,5-HT) receptors in NA neurones. Treatments with ADT was shown to provokealso a down-regulation of the 5-HT2 receptors in Sugrue M. F. et al,1981, Pharmacol. Ther. 13, 219-247. As a consequence, it appears thatthe NA and 5-HT systems play a crucial role in the regulation of moodand behaviour.

In the nineties, research has focused on the finding of specificserotonin re-uptake inhibitors (SSRI), such as fluoxetin, parxetin orsertralin (Pinder R. M. et al., 1993, Med. Res. Rev. 13, 259-325).Serotonin (5-hydroxytryptamine, or 5-HT) levels are controlled by theuptake of tryptophan and intraneuronal monoamine oxidase activity.

In the meantime, a decrease in the level of HVA, the main catabolic ofdopamin (DA), was observed in depressed patients (Kapur S. et al., 1992,Biol. Psychiat. 32, 1-17). GABA was also shown to be involved in thephysiopathology of depression since (i) unipolar patients displaydecreased level of GABA, (ii) some antidepressants induce the release ofGABA in vivo and (iii) agonists of GABA receptors have antidepressanteffects (Lloyd K. G. et al., 1989, Prog. Neuro-Psychopharmacol. Biol.Psychiat. 13, 341-351).

More recently, it has been reported that other factors may be involvedin CNS disorders. For example, it has been observed from 30 to 70% ofpatients afflicted with melancholia have high level of plasmaticcortisol and escape to the test with dexamethasone described in CarollB. J. et al. (1981), Arch. Gen. Psychiat. 38, 15.

In addition, corticosteroïds modify (i) the expression of serotoninergicreceptors and (ii) the activity of tryptophan hydroxylase, which is thekey enzyme in the synthesis of 5-HT (Biegon A., 1990, Ann. NY Acad. Sci.600, 427-431).

Regarding post-partum or post-menopause depression, repeatedadministration of oestrogene induces a down-regulation of dopaminergicD2 receptors (Munemura M. et al., 1989, Endocrinology 124, 346-355 andRoy E. J. et al., 1990, Brain. Res. Bull. 25, is 221-227).

Other neurotransmitters include the well known acetylcholine,norepinephrine which interacts with adrenergic receptors and which isregulated by tyrosine hydroxylase and monoamine oxidase, endorphinswhich are polypeptides that activate many central neurons and interactwith opioid receptors, enkephalins, dynorphins, histamine, vasopressin,vasoactive intestinal peptide, carnosine, bradykinin, cholecystokinin,bombesin, somatostatin, corticotropin releasing factor, neurotensin, andadenosine.

As mentioned above, any imbalance in these neurotransmitters or anyderegulation of associated receptors may lead to the development of CNSdisorders ranging from psychiatric diseases to migraine, pain, memoryloss and nerve cells degeneracy.

As of today, available treatments include selective serotonin reuptakeinhibitors (SSRIs) such as fluoxetine, sertraline, paroxetine, andfluvoxamine. Other compounds include nefazodone which blocks the 5-HT2receptor and inhibits reuptake of 5-HT and norepinephrine, trazodonewhich is a 5-HT2 receptor blocker and a 1-noradrenergic blocker,mirtazapine which blocks 2-adrenergic autoreceptors as well as 5-HT2,5-HT3 and H1 receptors, tricyclic compounds such as imipramine anddesipramine, tetracyclic compounds which increase the level of freenorepinephrine and of 5-HT, and monoamine oxidase inhibitors (MAOI)which inhibit the oxidative deamination of norepinephrine, dopamine, and5-HT. We can also cite lithium-antidepressants for treating bipolardisorder.

However, these compounds are only effective in about 65% of depressedpatients, which implies a large population afflicted with the so-called“refractory depression”. In some cases, the life of patients is injeopardy at the extent that hospitalization and electroconvulsivetherapy is required. This shows the seriousness of these diseases.Furthermore, the above mentioned compounds display numerous side effectsuch as tachycardia, sedation and weight gain.

Schizophrenia is also a serious mental disorder affecting about 1% ofwestern countries population. Antipsychotic (neuroleptic) drugsavailable include chlorpromazine and haloperidol which show affinity forthe dopamine 2 receptor. But, adverse side effects such as sedation,dystonia, tremors and akathisia have been commonly observed and asignificant percentage of patients do not respond to the treatments.

Therefore, the problem is to find alternative solutions to provide arelief and a cure for the numerous patients afflicted with thesediseases.

In connection with the present invention, we propose that mast cells areinvolved in or contribute to CNS disorders. Mast cells (MC) are tissueelements derived from a particular subset of hematopoietic stem cellsthat express CD34, c-kit and CD13 antigens (Kirshenbaum et al, Blood.94: 2333-2342, 1999 and Ishizaka et al, Curr Opin Immunol. 5: 937-43,1993). Immature MC progenitors circulate in the bloodstream anddifferentiate in tissues. These differentiation and proliferationprocesses are under the influence of cytokines, one of utmost importancebeing Stem Cell Factor (SCF), also termed Kit ligand (KL), Steel factor(SL) or Mast Cell Growth Factor (MCGF). SCF receptor is encoded by theprotooncogene c-kit, that belongs to type III receptor tyrosine kinasesubfamily (Boissan and Arock, J Leukoc Biol. 67: 135-48, 2000). Thisreceptor is also expressed on others hematopoietic or non hematopoieticcells. Ligation of c-kit receptor by SCF induces its dimerizationfollowed by its transphosphorylation, leading to the recruitement andactivation of various intracytoplasmic substrates. These activatedsubstrates induce multiple intracellular signaling pathways responsiblefor cell proliferation and activation (Boissan and Arock, 2000). Mastcells are characterized by their heterogeneity, not only regardingtissue location and structure but also at the functional andhistochemical levels (Aldenborg and Enerback., Histochem. J. 26: 587-96,1994 ; Bradding et al. J Immunol. 155: 297-307, 1995; Irani et al, JImmunol. 147: 247-53, 1991; Miller et al, Curr Opin Immunol. 1: 637-42,1989 and Welle et al, J Leukoc Biol. 61: 233-45, 1997).

Here, it is postulated that the activation of mast cells by differentstimuli such as stress, trauma, infection as well as neurotransmitters,participate in the exacerbation of the chemical imbalance causing CNSdisorders.

More specifically, mast cell degranulation is stimulated by commonneurotransmitters such as neurotensin, somatostatin, substance P andacetylcholine, by growth or survival factors, notably NGF, TGFβ1 (seeFIG. 1). Mast cells involved in the response to such stimulus can bebrain mast cells but also other mast cells releasing the content oftheir granules in the blood stream that ultimately reach sensory, motoror brain neurons. Brain mast cells staining is CTMC staining-like butthey show the secretory pattern of MMC, implying that they constitute aparticular subset of mast cells presenting specificities.

Following mast cells activation, released granules liberate variousfactors capable of modulating and altering neurotransmission and neuronssurvival. Among such factors, serotonin is important since an increaseof the level of free serotonin has been observed in depressed patients.Alternatively, the sudden burst of serotonin may be followed by a periodof serotonin shortage, leading to pain and migraine. As a consequence,we believe that mast cells exacerbate in autocrine or paracrine mannerthe deregulation of neurotransmission. For example, anxiety orstress-induced release of neurotransmitters such as serotonin activatesmast cells, which in turn release the content of their granules, furthercontributing to the chemical imbalance in the brain leading to CNSdisorders. Other mediators released by mast cells can be categorizedinto vasoactive, nociceptive, proinflammatory and otherneurotransmitters. Taken together, these factors are able to inducegreat disturbance in the activity of neurons, whether they are sensory,motor, or CNS neurons.

We also observed that patients afflicted with mastocytosis are moreincline to develop CNS disorders than the normal population. This can beexplained by the presence of activating mutations in the c-kit receptor,which induce degranulation of mast cells and a burst of factorscontributing to chemical imbalance and neurotransmission alteration.

In some cases, activated mast cells can also participate in thedestruction of neuronal tissues by releasing a cocktail of differentproteases and mediators categorized into three groups: preformedgranule-associated mediators (histamine, proteoglycans, and neutralproteases), lipid-derived mediators (prostaglandins, thromboxanes andleucotrienes), and various cytokines (IL-1, IL-2, IL-3, IL-4, IL-5,IL-6, IL-8, TNF-α, GM-CSF, MIP-1a, MIP-1b, MIP-2 and IFN-γ). Then,liberation by activated mast cells of mediators (TNF-α, histamine,leucotrienes, prostaglandines etc . . . ) as well as proteases isproposed here i) to induce inflammation and vasodilatation and ii) toparticipate in the neuronal tissue destruction process.

As a consequence, the present invention proposes to deplete mast cellsusing compounds that are substantially specific to mast cells. In thisregard, tyrosine kinase inhibitors and more particularly c-kit specifickinase inhibitors are proposed to inhibit mast cell proliferation,survival and activation.

A new route for treating CNS disorders is provided, which consists ofdestroying mast cells involved in and contributing to the pathogenesisof these disorders. It has been found that tyrosine kinase inhibitorsand more particularly c-kit inhibitors are especially suited to reachthis goal.

DESCRIPTION

The present invention relates to a method for treating CNS disorderscomprising administering a compound capable of depleting mast cells to ahuman in need of such treatment.

Said method for treating CNS disorders can comprise administering atyrosine kinase inhibitor to a human in need of such treatment.

Tyrosine kinase inhibitors are selected for example from bis monocyclic,bicyclic or heterocyclic aryl compounds (WO 92/20642),vinylene-azaindole derivatives (WO 94/14808) and1-cycloproppyl4-pyridyl-quinolones (U.S. Pat. No. 5,330,992), Styrylcompounds (U.S. Pat. No. 5,217,999), styryl-substituted pyridylcompounds (U.S. Pat. No. 5,302,606), seleoindoles and selenides (WO94/03427), tricyclic polyhydroxylic compounds (WO 92/21660) andbenzylphosphonic acid compounds (WO 91/15495), pyrimidine derivatives(U.S. Pat. No. 5,521,184 and WO 99/03854), indolinone derivatives andpyrrol-substituted indolinones (U.S. Pat. No. 5,792,783, EP 934 931,U.S. Pat. No. 5,834,504, U.S. Pat. No. 5,883,116, U.S. Pat. No.5,883,113, U.S. Pat. No. 5,886,020, WO 96/40116 and WO 00/38519), aswell as bis monocyclic, bicyclic aryl and heteroaryl compounds (EP 584222, U.S. Pat. No. 5,656,643 and WO 92/20642), quinazoline derivatives(EP 602 851, EP 520 722, U.S. Pat. No. 3,772,295 and U.S. Pat. No.4,343,940) and aryl and heteroaryl quinazoline (U.S. Pat. No. 5,721,237,U.S. Pat. No. 5,714,493, U.S. Pat. No. 5,710,158 and WO 95/15758).

Preferably, said tyrosine kinase inhibitors are unable to promote deathof IL-3 dependent cells cultured in presence of IL-3.

In another embodiment, the invention is directed to a method fortreating CNS disorders comprising administering a c-kit inhibitor to ahuman in need of such treatment.

Preferably, said c-kit inhibitor is a non-toxic, selective and potentc-kit inhibitor. Such inhibitors can be selected from the groupconsisting of indolinones, pyrimidine derivatives, pyrrolopyrimidinederivatives, quinazoline derivatives, quinoxaline derivatives, pyrazolesderivatives, bis monocyclic, bicyclic or heterocyclic aryl compounds,vinylene-azaindole derivatives and pyridyl-quinolones derivatives,styryl compounds, styryl-substituted pyridyl compounds, seleoindoles,selenides, tricyclic polyhydroxylic compounds and benzylphosphonic acidcompounds.

Among preferred compounds, it is of interest to focus on pyrimidinederivatives such as N-phenyl-2-pyrimidine-amine derivatives (U.S. Pat.No. 5,521,184 and WO 99/03854), indolinone derivatives andpyrrol-substituted indolinones (U.S. Pat. No. 5,792,783, EP 934 931,U.S. Pat. No. 5,834,504), U.S. Pat. No. 5,883,116, U.S. Pat. No.5,883,113, U.S. Pat. No. 5, 886,020, WO 96/40116 and WO 00/38519), aswell as bis monocyclic, bicyclic aryl and heteroaryl compounds (EP 584222, U.S. Pat. No. 5,656,643 and WO 92/20642), quinazoline derivatives(EP 602 851, EP 520 722, U.S. Pat. No. 3,772,295 and U.S. Pat. No.4,343,940), 4-amino-substituted quinazolines (U.S. Pat. No. 3,470,182),4-thienyl-2-(1H)-quinazolones, 6,7-dialkoxyquinazolines (U.S. Pat. No.3,800,039), aryl and heteroaryl quinazoline (U.S. Pat. No. 5,721,237,U.S. Pat. No. 5,714,493, U.S. Pat. No. 5,710,158 and WO 95/15758),4-anilinoquinazoline compounds (U.S. Pat. No. 4,464,375), and4-thienyl-2(1H)-quinazolones (U.S. Pat. No. 3,551,427).

So, preferably, the invention relates to a method for treating CNSdisorders comprising administering a non toxic, potent and selectivec-kit inhibitor is a pyrimidine derivatives, more particularlyN-phenyl-2-pyrimidine-amine derivatives of formula I:

wherein the R1, R2, R3, R13 to R17 groups have the meanings depicted inEP 564 409 B1, incorporated herein in the description.

Preferably, the N-phenyl-2-pyrimidine-amine derivative is selected fromthe compounds corresponding to formula II:

-   Wherein R1, R2 and R3 are independently chosen from H, F, Cl, Br, I,    a C1-C5 alkyl or a cyclic or heterocyclic group, especially a    pyridyl group;-   R4, R5 and R6 are independently chosen from H, F, Cl, Br, I, a C1-C5    alkyl, especially a methyl group;-   and R7 is a phenyl group bearing at least one substituent, which in    turn possesses at least one basic site, such as an amino function.

Preferably, R7 is the following group:

Among these compounds, the preferred are defined as follows:

-   R1 is a heterocyclic group, especially a pyridyl group,-   R2 and R3 are H,-   R4 is a C1-C3 alkyl, especially a methyl group,-   R5 and R6 are H,-   and R7 is a phenyl group bearing at least one substituent, which in    turn possesses at least one basic site, such as an amino function,    for example the group:

Therefore, in a preferred embodiment, the invention relates to a methodfor treating CNS disorders comprising the administration of an effectiveamount of the compound known in the art as CGP57148B:

-   4-(4-méhylpipérazine-1    -ylméthyl)-N-[4-méthyl-3-(4-pyridine-3-yl)pyrimidine-2ylamino)phényl]-benzamide    corresponding to the following formula:

The preparation of this compound is described in example 21 of EP 564409 and the β-form, which is particularly useful is described in WO99/03854.

Alternatively, the c-kit inhibitor can be selected from:

-   -   indolinone derivatives, more particularly pyrrol-substituted        indolinones,    -   monocyclic, bicyclic aryl and heteroaryl compounds, quinazoline        derivatives,    -   and quinaxolines, such as 2-phényl-quinaxoline derivatives, for        example 2-phenyl-6,7-dimethoxy quinaxoline.

In a preferred aspect, the invention contemplated the method mentionedabove, wherein said c-kit inhibitor is unable to promote death of IL-3dependent cells cultured in presence of IL-3.

The CNS disorders as referred herein include but are not limited topsychiatric disorders, migraine, pain, memory loss and nerve cellsdegeneracy.

More particularly, the method according to the invention is useful forthe treatment of the following disorders:

-   -   Depression including dysthymic disorder, cyclothymic disorder,        bipolar depression, severe or “melancholic” depression, atypical        depression, refractory depression, seasonal depression,        anorexia, bulimia, premenstrual syndrome, post-menopause        syndrome.    -   Other syndromes such as mental slowing and loss of        concentration, pessimistic worry, agitation, self-deprecation,        decreased libido,    -   Pain including, acute pain, postoperative pain, chronic pain,        nociceptive pain, cancer pain, neuropathic pain, psychogenic        pain syndromes,    -   Anxiety disorders including anxiety associated with        hyperventilation and cardiac arrhythmias, phobic disorders,        obsessive-compulsive disorder, posttraumatic stress disorder,        acute stress disorder, generalized anxiety disorder,    -   Psychiatric emergencies such as panic attacks, including        psychosis, delusional disorders, conversion disorders, phobias,        mania, delirium, dissociative episodes including dissociative        amnesia, dissociative fugue and dissociative identity disorder,        depersonalization, catatonia, seizures    -   Severe psychiatric emergencies including suicidal behaviour,        self-neglect, violent or aggressive behaviour, trauma,        borderline personality, and acute psychosis,    -   Schizophrenia including paranoid schizophrenia, disorganized        schizophrenia, catatonic schizophrenia, and undifferentiated        schizophrenia,    -   Neurodegenerative diseases including Alzheimer's disease ,        Parkinson's disease, Huntington's disease, the prion diseases,        Motor Neurone Disease (MND), and Amyotrophic Lateral Sclerosis        (ALS).

Therefore, in a preferred embodiment, the method of the invention isapplicable to the treatment of depression.

In another preferred embodiment, the method of the invention isapplicable to the treatment of pain.

In another preferred embodiment, the method of the invention isapplicable to the treatment of anxiety disorders.

In another preferred embodiment, the method of the invention isapplicable to the treatment of psychiatric disorders.

In another preferred embodiment, the method of the invention isapplicable to the treatment of schizophrenia.

In another preferred embodiment, the method of the invention isapplicable to the treatment of neurodegenerative diseases.

The method as depicted above is also useful for treating memory loss.

In still another preferred embodiment, the method of the invention isapplicable to the treatment of migraine.

In a further embodiment, c-kit inhibitors as mentioned above areinhibitors of activated c-kit. In frame with the invention, theexpression “activated c-kit” means a constitutively activated-mutantc-kit including at least one mutation selected from point mutations,deletions, insertions, but also modifications and alterations of thenatural c-kit sequence (SEQ ID N^(o). 1). Such mutations, deletions,insertions, modifications and alterations can occur in thetransphosphorylase domain, in the juxtamembrane domain as well as in anydomain directly or indirectly responsible for c-kit activity. Theexpression “activated c-kit” also means herein SCF-activated c-kit.Preferred and optimal SCF concentrations for activating c-kit arecomprised between 5.10⁻⁷ M and 5.10⁻⁶ M, preferably around 2.10⁻⁶ M. Ina preferred embodiment, the activated-mutant c-kit in step a) has atleast one mutation proximal to Y823, more particularly between aminoacids 800 to 850 of SEQ ID No 1 involved in c-kit autophosphorylation,notably the D816V, D816Y, D816F and D820G mutants. In another preferredembodiment, the activated-mutant c-kit in step a) has a deletion in thejuxtamembrane domain of c-kit. Such a deletion is for example betweencodon 573 and 579 called c-kit d(573-579). The point mutation V559Gproximal to the juxtamembrane domain c-kit is also of interest.

In this regard, the invention contemplates a method for treating CNSdisorders as defined above comprising administering to a human in needof such treatment a compound that is a selective, potent and non toxicinhibitor of activated c-kit obtainable by a screening method whichcomprises:

-   a) bringing into contact (i) activated c-kit and (ii) at least one    compound to be tested; under conditions allowing the components (i)    and (ii) to form a complex,-   b) selecting compounds that inhibit activated c-kit,-   c) testing and selecting a subset of compounds identified in step    b), which are unable to promote death of IL-3 dependent cells    cultured in presence of IL-3.

This screening method can further comprise the step consisting oftesting and selecting a subset of compounds identified in step b) thatare inhibitors of mutant activated c-kit (for example in thetransphosphorylase domain), which are also capable of inhibitingSCF-activated c-kit wild.

Alternatively, in step a) activated c-kit is SCF-activated c-kit wild.

A best mode for practicing this method consists of testing putativeinhibitors at a concentration above 10 μM in step a). Relevantconcentrations are for example 10, 15, 20, 25, 30, 35 or 40 μM.

In step c), IL-3 is preferably present in the culture media of IL-3dependent cells at a concentration comprised between 0.5 and 10 ng/ml,preferably between 1 to 5 ng/ml.

Examples of IL-3 dependent cells include but are not limited to:

cell lines naturally expressing and depending on c-kit for growth andsurvival. Among such cells, human mast cell lines can be establishedusing the following procedures: normal human mast cells can be infectedby retroviral vectors containing sequences coding for a mutant c-kitcomprising the c-kit signal peptide and a TAG sequence allowing todifferentiate mutant c-kits from c-kit wild expressed in hematopoeticcells by means of antibodies.

This technique is advantageous because it does not induce cellularmortality and the genetic transfer is stable and gives satisfactoryyields (around 20%). Pure normal human mast cells can be routinelyobtained by culturing precursor cells originating from blood obtainedfrom human umbilical vein. In this regard, heparinated blood fromumbilical vein is centrifuged on a Ficoll gradient so as to isolatemononucleated cells from other blood components. CD34+ precursor cellsare then purified from the isolated cells mentioned above using theimmunomagnetic selection system MACS (Miltenyi biotech). CD34+ cells arethen cultured at 37° C. in 5% CO₂ atmosphere at a concentration of 10⁵cells per ml in the medium MCCM (α-MEM supplemented with L-glutamine,penicillin, streptomycin, 5 10⁻⁵ M β-mercaptoethanol, 20% veal foetalserum, 1% bovine albumin serum and 100 ng/ml recombinant human SCF. Themedium is changed every 5 to 7 days. The percentage of mast cellspresent in the culture is assessed each week, using May-Grünwal Giemsaor Toluidine blue coloration. Anti-tryptase antibodies can also be usedto detect mast cells in culture. After 10 weeks of culture, a purecellular population of mast cells (>98%) is obtained.

It is possible using standard procedures to prepare vectors expressingc-kit for transfecting the cell lines established as mentioned above.The cDNA of human c-kit has been described in Yarden et al., (1987) EMBOJ.6 (11), 3341-3351. The coding part of c-kit (3000 bp) can be amplifiedby PCR and cloned, using the following oligonucleotides:5′AAGAAGAGATGGTACCTCGAGGGGTGACCC3′ (SEQ ID No 2) sens5′CTGCTTCGCGGCCGCGTTAACTCTTCTCAACCA3′ (SEQ ID No 3) antisens

The PCR products, digested with Not1 and Xho1, has been inserted usingT4 ligase in the pFlag-CMV vector (SIGMA), which vector is digested withNot1 and Xho1 and dephosphorylated using CIP (Biolabs). ThepFlag-CMV-c-kit is used to transform bacterial clone XL1-blue. Thetransformation of clones is verified using the following primers:5′AGCTCGTTTAGTGAACCGTC3′ (SEQ ID No 4) sens, 5′GTCAGACAAAATGATGCAAC3′(SEQ ID No 5) antisens.

Directed mutagenesis is performed using relevant cassettes is performedwith routine and common procedure known in the art.

The vector Migr-1 (ABC) can be used as a basis for constructingretroviral vectors used for transfecting mature mast cells. This vectoris advantageous because it contains the sequence coding for GFP at the3′ and of an IRES. These features allow to select cells infected by theretrovirus using direct analysis with a fluorocytometer. As mentionedabove, the N-terminal sequence of c-kit c-DNA can be modified so as tointroduce a Flag sequence that will be useful to discriminatingheterogeneous from endogenous c-kit.

Other IL-3 dependent cell lines that can be used include but are notlimited to:

-   BaF3 mouse cells expressing wild-type or mutated form of c-kit (in    the juxtamembrane and in the catalytic sites) are described in    Kitayama et al, (1996), Blood 88, 995-1004 and Tsujimura et al,    (1999), Blood 93, 1319-1329.-   IC-2 mouse cells expressing either c-kit^(WT) or c-kit^(D814Y) are    presented in Piao et al, (1996), Proc. Natl. Acad. Sci. USA 93,    14665-14669.

IL-3 independent cell lines are:

-   HMC-1, a factor-independent cell line derived from a patient with    mast cell leukemia, expresses a juxtamembrane mutant c-kit    polypeptide that has constitutive kinase activity (Furitsu T et al,    J Clin Invest. 1993;92:1736-1744; Butterfield et al, Establishment    of an immature mast cell line from a patient with mast cell    leukemia. Leuk Res. 1988;12:345-355 and Nagata et al, Proc Natl Acad    Sci USA. 1995;92:10560-10564).-   P815 cell line (mastocytoma naturally expressing c-kit mutation at    the 814 position) has been described in Tsujimura et al, (1994),    Blood 83, 2619-2626.

The extent to which component (ii) inhibits activated c-kit can bemeasured in vitro or in vivo. In case it is measured in vivo, cell linesexpressing an activated-mutant c-kit, which has at least one mutationproximal to Y823, more particularly between amino acids 800 to 850 ofSEQ ID No 1 involved in c-kit autophosphorylation, notably the D816V,D816Y, D816F and D820G mutants, are preferred.

Example of cell lines expressing an activated-mutant c-kit are asmentioned above.

In another preferred embodiment, the method further comprises the stepconsisting of testing and selecting compounds capable of inhibitingc-kit wild at concentration below 1 μM. This can be measured in vitro orin vivo.

Therefore, compounds are identified and selected according to the methoddescribed above are potent, selective and non-toxic c-kit wildinhibitors.

Alternatively, the screening method as defined above can be practiced invitro. In this regard, the inhibition of mutant-activated c-kit and/orc-kit wild can be measured using standard biochemical techniques such asimmunoprecipitation and western blot. Preferably, the amount of c-kitphosphorylation is measured.

In a still further embodiment, the invention contemplates a method fortreating CNS disorders as depicted above wherein the screeningcomprises:

-   a) performing a proliferation assay with cells expressing a mutant    c-kit (for example in the transphosphorylase domain), which mutant    is a permanent activated c-kit, with a plurality of test compounds    to identify a subset of candidate compounds targeting activated    c-kit, each having an IC50<10 μM, by measuring the extent of cell    death,-   b) performing a proliferation assay with cells expressing c-kit wild    said subset of candidate compounds identified in step (a), said    cells being IL-3 dependent cells cultured in presence of IL-3, to    identify a subset of candidate compounds targeting specifically    c-kit,-   c) performing a proliferation assay with cells expressing c-kit,    with the subset of compounds identified in step b) and selecting a    subset of candidate compounds targeting c-kit wild, each having an    IC50<10 μM, preferably an IC50<μM, by measuring the extent of cell    death.

Here, the extent of cell death can be measured by 3H thymidineincorporation, the trypan blue exclusion method or flow cytometry withpropidium iodide. These are common techniques routinely practiced in theart.

The method according to the invention includes preventing, delaying theonset and/or treating CNS disorders in humans. Regarding the priondiseases, the invention encompasses the treatment of mammals such asbovine and ovine species.

In the method defined above, any compound capable of depleting mastcells can be used. Such compounds can belong to, as explicated above,tyrosine kinase inhibitors, such as c-kit inhibitors, but are notlimited to any particular family so long as said compound showscapabilities to deplete mast cells. Depletion of mast cells can beevaluated using for example one of the mast cell lines depicted aboveusing routine procedure.

Best compounds are compounds exhibiting the greatest selectivity.

Control cell lines include other hematopoeitic cells that are not mastcells or related cells or cell lines. These control cell lines includeSCF independent expanded human CD34+ normal cells. These control cellsalso include but are not limited to the human T lymphocyte Jurkat cellline (ATCC N^(o) TIB-152 and mutant cell lines derived thereof), thehuman B lymphocyte Daudi or Raji cell line (ATCC N^(o) CCL-213 andCCL-86 respectively), the human monocytic U 937 cell line (ATCC N^(o)CRL-1593.2) and the human HL-60 cell line (ATCC N^(o) CCL-240) andmutant cell lines derived thereof CRL-2258 and CRL-2392).

Such compounds can be selected with a method for identifying compoundscapable of depleting mast cells, said compound being non-toxic for celltypes other than mast cells, comprising the step consisting of:

-   a) culturing mast cells in vitro in a culture medium suitable for    mast cells,-   b) adding to said culture medium at least one compound to be tested    and incubating said cells for a prolonged period of time,-   c) selecting compounds that promote mast cells death,-   d) identifying a subset of compounds selected in step c) that are    unable to promote death of cells selected from the above mentioned    control cell lines.

Therefore, the invention embraces the use of the compounds defined aboveto manufacture a medicament for treating CNS disorders such aspsychiatric disorders, migraine, pain, memory loss and nerve cellsdegeneracy.

The invention is also directed to the use of the compounds defined aboveto manufacture a medicament for treating a disorders selected from thesubgroups consisting of:

-   -   Depression including dysthymic disorder, cyclothymic disorder,        bipolar depression, severe or “melancholic” depression, atypical        depression, seasonal depression, anorexia, bulimia, premenstrual        syndrome, post-menopause syndrome.    -   Other syndromes such as mental slowing and loss of        concentration, pessimistic worry, agitation, self-deprecation,        decreased libido,    -   Pain including, acute pain, postoperative pain, chronic pain,        nociceptive pain, cancer pain, neuropathic pain, psychogenic        pain syndromes,    -   Anxiety disorders including anxiety associated with        hyperventilation and cardiac arrhythmias, phobic disorders,        obsessive-compulsive disorder, posttraumatic stress disorder,        acute stress disorder, generalized anxiety disorder,    -   Psychiatric emergencies such as panic attacks, including        psychosis, delusional disorders, conversion disorders, phobias,        mania, delirium, dissociative episodes including dissociative        amnesia, dissociative fugue and dissociative identity disorder,        depersonalization, catatonia, seizures    -   Severe psychiatric emergencies including suicidal behaviour,        self-neglect, violent or aggressive behaviour, trauma,        borderline personality, and acute psychosis,    -   Schizophrenia including paranoid schizophrenia, disorganized        schizophrenia, catatonic schizophrenia, and undifferentiated        schizophrenia,    -   Neurodegenerative diseases including Alzheimer's disease ,        Parkinson's disease, Huntington's disease, the prion diseases,        Motor Neurone Disease (MND), and Amyotrophic Lateral Sclerosis        (ALS).

The pharmaceutical compositions utilized in this invention may beadministered by any number of routes including, but not limited to,oral, intravenous, intramuscular, intra-arterial, intramedullary,intrathecal, intraventricular, transdermal, subcutaneous,intraperitoneal, intranasal, enteral, topical, sublingual, or rectalmeans.

In addition to the active ingredients, these pharmaceutical compositionsmay contain suitable pharmaceutically-acceptable carriers comprisingexcipients and auxiliaries which facilitate processing of the activecompounds into preparations which can be used pharmaceutically. Furtherdetails on techniques for formulation and administration may be found inthe latest edition of Remington's Pharmaceutical Sciences (MaackPublishing Co., Easton, Pa.).

Pharmaceutical compositions for oral administration can be formulatedusing pharmaceutically acceptable carriers well known in the art indosages suitable for oral administration. Such carriers enable thepharmaceutical compositions to be formulated as tablets, pills, dragees,capsules, liquids, gels, syrups, slurries, suspensions, and the like,for ingestion by the patient.

More particularly, the invention relates to a pharmaceutical compositionintended for oral administration.

Regarding the treatment of pain, topical administration may be mostsuitable in some cases. Here, the compositions according to theinvention may be presented in the form of a gel, paste, ointment, cream,lotion, liquid suspension aqueous, aqueous-alcoholic or, oily solutions,or dispersions of the lotion or serum type, or anhydrous or lipophilicgels, or emulsions of liquid or semi-solid consistency of the milk type,obtained by dispersing a fatty phase in an aqueous phase or vice versa,or of suspensions or emulsions of soft, semi-solid consistency of thecream or gel type, or alternatively of microemulsions, of microcapsules,of microparticles or of vesicular dispersions to the ionic and/ornonionic type. These compositions are prepared according to standardmethods.

The composition according to the invention comprises any ingredientcommonly used in dermatology and cosmetic. It may comprise at least oneingredient selected from hydrophilic or lipophilic gelling agents,hydrophilic or lipophilic active agents, preservatives, emollients,viscosity enhancing polymers, humectants, surfactants, preservatives,antioxidants, solvents, and fillers, antioxidants, solvents, perfumes,fillers, screening agents, bactericides, odor absorbers and coloringmatter.

As oils which can be used in the invention, mineral oils (liquidparaffin), vegetable oils (liquid fraction of shea butter, sunfloweroil), animal oils, synthetic oils, silicone oils (cyclomethicone) andfluorinated oils may be mentioned. Fatty alcohols, fatty acids (stearicacid) and waxes (paraffin, camauba, beeswax) may also be used as fattysubstances.

As emulsifiers which can be used in the invention, glycerol stearate,polysorbate 60 and the PEG-6/PEG-32/glycol stearate mixture arecontemplated.

As hydrophilic gelling agents, carboxyvinyl polymers (carbomer), acryliccopolymers such as acrylate/alkylacrylate copolymers, polyacrylamides,polysaccharides such as hydroxypropylcellulose, clays and natural gumsmay be mentioned, and as lipophilic gelling agents, modified clays suchas bentones, metal salts of fatty acids such as aluminum stearates andhydrophobic silica, or alternatively ethylcellulose and polyethylene maybe mentioned.

As hydrophilic active agents, proteins or protein hydrolysates, aminoacids, polyols, urea, allantoin, sugars and sugar derivatives, vitamins,starch and plant extracts, in particular those of Aloe vera may be used.

As lipophilic active, agents, retinol (vitamin A) and its derivatives,tocopherol (vitamin E) and its derivatives, essential fatty acids,ceramides and essential oils may be used. These agents add extramoisturizing or skin softening features when utilized.

In addition, a surfactant can be included in the composition so as toprovide deeper penetration of the compound capable of depleting mastcells, such as a tyrosine kinase inhibitor, preferably a c-kitinhibitor.

Among the contemplated ingredients, the invention embraces penetrationenhancing agents selected for example from the group consisting ofmineral oil, water, ethanol, triacetin, glycerin and propylene glycol;cohesion agents selected for example from the group consisting ofpolyisobutylene, polyvinyl acetate and polyvinyl alcohol, and thickeningagents.

Chemical methods of enhancing topical absorption of drugs are well knownin the art. For example, compounds with penetration enhancing propertiesinclude sodium lauryl sulfate (Dugard, P. H. and Sheuplein, R. J.,“Effects of Ionic Surfactants on the Permeability of Human Epidermis: AnElectrometric Study,” J. Ivest. Dermatol., V.60, pp. 263-69, 1973),lauryl amine oxide (Johnson et. al., U.S. Pat. No. 4,411,893), azone(Rajadhyaksha, U.S. Pat. Nos. 4,405,616 and 3,989,816) and decylmethylsulfoxide (Sekura, D. L. and Scala, J., “The Percutaneous Absorption ofAlkylmethyl Sulfides,” Pharmacology of the Skin, Advances In Biolocy ofSkin, (Appleton-Century Craft) V. 12, pp. 257-69, 1972). It has beenobserved that increasing the polarity of the head group in amphotericmolecules increases their penetration-enhancing properties but at theexpense of increasing their skin irritating properties (Cooper, E. R.and Berner, B., “Interaction of Surfactants with Epidermal Tissues:Physiochemical Aspects,” Surfactant Science Series, V. 16, Reiger, M. M.ed. (Marcel Dekker, Inc.) pp. 195-210, 1987).

A second class of chemical enhancers are generally referred to asco-solvents. These materials are absorbed topically relatively easily,and, by a variety of mechanisms, achieve permeation enhancement for somedrugs. Ethanol (Gale et. al., U.S. Pat. No. 4,615,699 and Campbell et.al., U.S. Pat. Nos. 4,460,372 and 4,379,454), dimethyl sulfoxide (U.S.Pat. Nos. 3,740,420 and 3,743,727, and U.S. Pat. No. 4,575,515), andglycerine derivatives (U.S. Pat. No. 4,322,433) are a few examples ofcompounds which have shown an ability to enhance the absorption ofvarious compounds.

Pharmaceutical compositions suitable for use in the invention includecompositions wherein compounds for depleting mast cells, such astyrosine kinase inhibitors and c-kit inhibitors, are contained in aneffective amount to achieve the intended purpose. The determination ofan effective dose is well within the capability of those skilled in theart. therapeutically effective dose refers to that amount of activeingredient, which ameliorates the symptoms or condition. Therapeuticefficacy and toxicity may be determined by standard pharmaceuticalprocedures in cell cultures or experimental animals, e.g., ED50 (thedose therapeutically effective in 50% of the population) and LD50 (thedose lethal to 50% of the population). The dose ratio of toxic totherapeutic effects is the therapeutic index, and it can be expressed asthe ratio, LD50/ED50. Pharmaceutical compositions which exhibit largetherapeutic indices are preferred. As mentioned above, a tyrosine kinaseinhibitor and more particularly a c-kit inhibitor according to theinvention is unable to promote death of IL-3 dependent cells cultured inpresence of IL-3.

The invention also contemplates a product comprising at least onecompound capable of depleting mast cells, such as a tyrosine kinaseinhibitors, more particularly a non-toxic, selective and potent c-kitinhibitor and at least one antidepressant, antipsychotic, or anxiolyticfor simultaneous, separate or sequential use for the treatment of CNSdisorders as defined above.

1. A method for treating CNS disorders comprising administering acompound capable of depleting mast cells to a human in need of suchtreatment.
 2. A method according to claim 1 for treating CNS disorderscomprising administering a tyrosine kinase inhibitor to a human in needof such treatment.
 3. A method according to claim 2, wherein saidtyrosine kinase inhibitor is unable to promote death of IL-3 dependentcells cultured in presence of IL-3.
 4. A method according to claim 2 fortreating CNS disorders comprising administering a c-kit inhibitor to ahuman in need of such treatment.
 5. A method according to claim 4,wherein said c-kit inhibitor is a non-toxic, selective and potent c-kitinhibitor.
 6. A method according to claim 5, wherein said inhibitor isselected from the group consisting of indolinones, pyrimidinederivatives, pyrrolopyrimidine derivatives, quinazoline derivatives,quinoxaline derivatives, pyrazoles derivatives, bis monocyclic, bicyclicor heterocyclic aryl compounds, vinylene-azaindole derivatives andpyridyl-quinolones derivatives, styryl compounds, styryl-substitutedpyridyl compounds, seleoindoles, selenides, tricyclic polyhydroxyliccompounds and benzylphosphonic acid compounds.
 7. A method according toclaim 5, wherein said inhibitor is selected from the group consistingof: pyrimidine derivatives, more particularlyN-phenyl-2-pyrimidine-amine derivatives. indolinone derivatives, moreparticularly pyrrol-substituted indolinones, monocyclic, bicyclic aryland heteroaryl compounds, and quinazoline derivatives.
 8. A methodaccording to claim 4, wherein said inhibitor is selected from the groupconsisting of N-phenyl-2-pyrimidine-amine derivatives having the formulaII:

Wherein R1, R2 and R3 are independently chosen from H, F, Cl, Br, I, aC1-C5 alkyl or a cyclic or heterocyclic group, especially a pyridylgroup; R4, R5 and R6 are independently chosen from H, F, Cl, Br, I, aC1-C5 alkyl, especially a methyl group; and R7 is a phenyl group bearingat least one substituent, which in turn possesses at least one basicsite, such as an amino function, preferably the following group:


9. A method according to claim 8, wherein said inhibitor is the4-(4-méhylpipérazine-1-ylméthyl)-N-[4-méthyl-3-(4-pyridine-3-yl)pyrimidine-2ylamino)phényl]-benzamide.
 10. A method according to one of claims 4 to9, wherein said c-kit inhibitor is unable to promote death of IL-3dependent cells cultured in presence of IL-3.
 11. A method according toone of claims 4 to 10, wherein said c-kit inhibitor is an inhibitor ofactivated c-kit.
 12. A method according to claim 11, wherein saidinhibitor is capable of inhibiting constitutively activated-mutantc-kit.
 13. A method according to one of claims 4 to 10, wherein saidactivated c-kit inhibitor is capable of inhibiting SCF-activated c-kit.14. A method for treating CNS disorders comprising administering to ahuman in need of such treatment a compound that is a selective, potentand non toxic inhibitor of activated c-kit obtainable by a screeningmethod which comprises: a) bringing into contact (i) activated c-kit and(ii) at least one compound to be tested; under conditions allowing thecomponents (i) and (ii) to form a complex, b) selecting compounds thatinhibit activated c-kit, c) testing and selecting a subset of compoundsidentified in step b), which are unable to promote death of IL-3dependent cells cultured in presence of IL-3.
 15. A method according toclaim 14, wherein the screening method further comprises the stepconsisting of testing and selecting a subset of compounds identified instep b) that are inhibitors of mutant activated c-kit, which are alsocapable of inhibiting SCF-activated c-kit wild.
 16. A method accordingto claim 14, wherein activated c-kit is SCF-activated c-kit wild in stepa).
 17. A method according to one of claims 14 to 16, wherein putativeinhibitors are tested at a concentration above 10 μM in step a).
 18. Amethod according to one of claims 14 to 16, wherein IL-3 is preferablypresent in the culture media of IL-3 dependent cells at a concentrationcomprised between 0.5 and 10 ng/ml, preferably between 1 to 5 ng/ml. 19.A method according to claim 14, wherein IL-3 dependent cells areselected from the group consisting of mast cells, transfected mastcells, BaF3 and IC-2.
 20. A method according to one of claims 14 to 19,wherein the extent to which component (ii) inhibits activated c-kit ismeasured in vitro or in vivo.
 21. A method according to one of claims 14to 20, further comprising the step consisting of testing and selectingcompounds capable of inhibiting c-kit wild at concentration below 1 μM.22. A method according to claim 17 or 21, wherein the testing isperformed in vitro or in vivo.
 23. A method according to one of claims14 to 22, wherein the inhibition of mutant-activated c-kit and/or c-kitwild is measured using standard biochemical techniques such asimmunoprecipitation and western blot.
 24. A method according to one ofclaims 14 to 22, wherein the amount of c-kit phosphorylation ismeasured.
 25. A method according to one of claims 14 to 24, whereinidentified and selected compounds are potent, selective and non-toxicc-kit wild inhibitors.
 26. A method for treating CNS disorderscomprising administering to a human in need of such treatment a c-kitinhibitor obtainable by a screening method comprising: a) performing aproliferation assay with cells expressing a mutant c-kit (for example inthe transphosphorylase domain), which mutant is a permanent activatedc-kit, with a plurality of test compounds to identify a subset ofcandidate compounds targeting activated c-kit, each having an IC50<10μM, by measuring the extent of cell death, b) performing a proliferationassay with cells expressing c-kit wild said subset of candidatecompounds identified in step (a), said cells being IL-3 dependent cellscultured in presence of IL-3, to identify a subset of candidatecompounds targeting specifically c-kit, c) performing a proliferationassay with cells expressing c-kit, with the subset of compoundsidentified in step b) and selecting a subset of candidate compoundstargeting c-kit wild, each having an IC50<10 μM, preferably an IC50<1μM, by measuring the extent of cell death.
 27. A method according toclaim 26, wherein the extent of cell death is measured by 3H thymidineincorporation, the trypan blue exclusion method or flow cytometry withpropidium iodide.
 28. A method according to one of claims 1 to 27 forpreventing, delaying the onset and/or treating CNS disorders in human.29. A method according to one of claims 1 to 28 for treating psychiatricdisorders, migraine, pain, memory loss and nerve cells degeneracy.
 30. Amethod according to one of claims 1 to 28 for treating depressionincluding dysthymic disorder, cyclothymic disorder, bipolar depression,severe or “melancholic” depression, atypical depression, refractorydepression, seasonal depression, anorexia, bulimia, premenstrualsyndrome and post-menopause syndrome.
 31. A method according to one ofclaims 1 to 28 for treating mental slowing and loss of concentration,pessimistic worry, agitation, self-deprecation and decreased libido. 32.A method according to one of claims 1 to 28 for treating pain including,acute pain, postoperative pain, chronic pain, nociceptive pain, cancerpain, neuropathic pain, and psychogenic pain syndromes.
 33. A methodaccording to one of claims 1 to 28 for treating anxiety disordersincluding anxiety associated with hyperventilation and cardiacarrhythmias, phobic disorders, obsessive-compulsive disorder,posttraumatic stress disorder, acute stress disorder, and generalizedanxiety disorder.
 34. A method according to one of claims 1 to 28 fortreating psychiatric disorders such as panic attacks, includingpsychosis, delusional disorders, conversion disorders, phobias, mania,delirium, dissociative episodes including dissociative amnesia,dissociative fugue and dissociative identity disorder,depersonalization, catatonia, and seizures.
 35. A method according toone of claims 1 to 28 for treating severe psychiatric disordersincluding suicidal behaviour, self-neglect, violent or aggressivebehaviour, trauma, borderline personality, and acute psychosis.
 36. Amethod according to one of claims 1 to 28 for treating schizophreniaincluding paranoid schizophrenia, disorganized schizophrenia, catatonicschizophrenia, and undifferentiated schizophrenia.
 37. A methodaccording to one of claims 1 to 28 for treating neurodegenerativediseases including Alzheimer's disease, Parkinson's disease,Huntington's disease, the prion diseases, Motor Neurone Disease (MND),and Amyotrophic Lateral Sclerosis (ALS).
 38. A method according to oneof claims 1 to 28 for treating memory loss.
 39. A method according toone of claims 1 to 28 for treating migraine.
 40. Use of a c-kitinhibitor to manufacture a medicament for treating CNS disorders, moreparticularly for the treatment of psychiatric disorders, migraine, pain,memory loss and nerve cells degeneracy.
 41. A composition suitable fortopical administration comprising a compound capable of depleting mastcells, preferably a tyrosine kinase inhibitor, more particularly a c-kitinhibitor for the treatment of pain.
 42. A composition suitable for oraladministration comprising a compound capable of depleting mast cells,preferably a tyrosine kinase inhibitor, more particularly a c-kitinhibitor for the treatment of CNS disorders, more particularly for thetreatment of psychiatric disorders, migraine, pain, memory loss andnerve cells degeneracy.
 43. A composition suitable for intravenous,intramuscular, intra-arterial, intramedullary, intrathecal,intraventricular, transdermal, subcutaneous, intraperitoneal, enteral,sublingual, or rectal administration comprising a compound capable ofdepleting mast cells, preferably a tyrosine kinase inhibitor, moreparticularly a c-kit inhibitor for the treating of CNS disorders, moreparticularly for the treatment of psychiatric disorders, migraine, pain,memory loss and nerve cells degeneracy.
 44. A product comprising atleast one compound capable of depleting mast cells, such as a tyrosinekinase inhibitors, more particularly a non-toxic, selective and potentc-kit inhibitor and at least one antidepressant, antipsychotic, oranxiolytic for simultaneous, separate or sequential use for thetreatment of CNS disorders, more particularly for the treatment ofpsychiatric disorders, migraine, pain, memory loss and nerve cellsdegeneracy.